1. Statement of the Invention
The present invention relates to an apparatus for high-temperature thermal applications for ball grid array semiconductor devices and a method of packaging ball grid array semiconductor devices.
2. State of the Art
Integrated semiconductor devices are typically constructed in wafer form with each device having the form of an integrated circuit die which is typically attached to a lead frame with gold wires. The die and lead frame are then encapsulated in a plastic or ceramic package, which is then commonly referred to as an integrated circuit (IC). ICs come in a variety of forms, such as a dynamic random access memory (DRAM), static random access memory (SRAM), read only memory (ROM), gate arrays, etc. The ICs are interconnected in many combinations on printed circuit boards by a number of techniques, such as socketing and soldering. Interconnection among ICs arrayed on a printed circuit board is typically made by conductive traces formed by photolithography and etching processes.
Such semiconductor devices typically take the form of the semiconductor die therein. The die is generally electrically attached to a lead frame within a package. The lead frame physically supports the die and provides electrical connections between the die and its operating environment. The die is generally electrically attached to the lead frame by means of fine gold wires. These fine gold wires function to connect the die to the lead frame so that the gold wires are connected electrically in series with the lead frame leads. The lead frame and die are then encapsulated. The packaged chip is then able to be installed on a circuit board by any desired manner, such as soldering, socketing, etc.
However, as the speed of the semiconductor die increases, the heat generated during operation increases. Additionally, it becomes necessary to shorten the leads between the printed circuit board on which the IC is located and the IC device itself in order to keep the impedance of the circuit from affecting the response speed of the IC device.
The wires connecting the leads of the lead frame to the bond pads on the active surface of the semiconductor die in an IC package are not an effective connection for high operating speed semiconductor dice as the wires slow down the response of the semiconductor die.
Therefore, a packaging is required for semiconductor dice which have high operating speeds and generate heat associated therewith while minimizing the lead length between the semiconductor dice and the printed circuit boards on which they are mounted.